Week 3 Challenge : CFD meshing on Turbocharger
Aim:
For the given model of a turbocharger, check for the geometrical errors to make appropriate volumes. Create and assign PIDs accordingly. Create surface mesh and use that to create a volumetric mesh.
Objective:
1. Perform surface mesh with the given target lengths as per PIDs.
- Blade stage-1 = 1 mm
- Blade stage-2 = 1 mm
- Impeller = 2 mm
- Shaft rotor = 1 mm
- Turbo casing = 5 mm
- Compressor casing = 5 mm
- Inlet casing cover = 5 mm
2. Performing Volumetric mesh for the required volumes.
3. Write a detailed report on your surface meshing & Volume meshing process.
Turbocharger Model:
(a) Model before Geometry Clean-Up
(b) Model after Geometric Clean-Up
Procedure:
1. Topo/ geometry clean-up:
(a). Upload the ANSA file using the open option under file drop down.
(b). Start with the topo clean by doing geometry check to find single and triple cons in the geometry. select topo under faces and box select the entire model so that any missing cons can be detected and the geometry clean up can be done more accurately.
(c). Delete the unecessary overlapping surfaces by using the universal delete option.
(d).Start with fill the surface and clearing the single cons by creating surface where ever required.
(e).Using Transform to Option to create a Surface folowing were the steps
Inserting HOT POINT to make it as a refrence point to create the given surface
select copy option
selecting the surface to copy
Selecting the refrence points
filling the hole using FILL HOLES option
(f).Deleting Unwanted surfaces
using the project command to divide the surface into 2 and deleting the unwanted surface
Deleting the surface below of shaft to eliminate Triple cones
2. Surface meshing:
1. We need to mesh each component as per the given criteria in the question, therefore we need to mesh the component individually.
2. Enter the quality and mesh parameters and length of the mesh accordingly for each component.
3. while entering the mesh length, be aware of the change in mesh length between components with different mesh length, when they come in contact they tend to erase the other mesh, therefore while entering the perimeter and macros we need to give a range ranging from the bigger to smaller mesh length to avoid the mesh to get erased.
4. After the mesh is generated, we can create a boundary of the varrying mesh length and maintain a constant mesh length on the other side of the boundary.
3. Volume meshing:
1. After the surface meshing is done, we can now achieve volume meshing.
2. Under volume meshing, choose define and select whole db in the pop up window.
Identifying volume using the define option
3. ANSA identifies various volume present in the geometry, we can delete the unwanted ones and keep the necessary volumes where the fluid can possibly flow in geometry.
Detected volumes present in the geometry
4. After the deleting the outer thickness volume and only keeping the fluid volume region, we can remesh each volume using the tetra CFD option under remesh.
Creating Tetra CFD volume mesh for the fluid volume region
5. After each volume is remeshed, the volume mesh can be viewed for each component.
Volume mesh created for each volume and cut section to view the 3D mesh
Learning outcome:
1. Checking for geometry errors and correcting the geometry using different geometry editting tools.
2. Deleting overlapping regions to improve mesh quality and avoid errors while volume meshing.
3. Correcting the triple cons and single cons accordingly as per the geometry requirement.
4. Using fine under auxileries helps in giving a finer surafce finish at the connecting region.
5. Creating surface mesh individually and also maintaining mesh length range at the contact region between 2 different mesh lengths.
6. Identifying and creating volume mesh only for the fluid region part.
7. Tools to create volume mesh.
Results:
1. Completed geometry clean-up with all the inlets and outlets closed to create a closed volume:
2. Surface Meshing achieved with different mesh lengths as per the question:
3. Volume mesh created for the fluid volume region along with cut sections to view the 3D mesh:
Conclusions:
1. Overlapped surface can be deleted using the universal delete option.
2. Unecessary single and triple cons can be removed and editted using different tools such as cons project, topo, release and fine tools while goemetry clean up.
3. Successfull volumetric mesh can be achieved only after correct geometric clean up and surface mesh.
4.Achieved volumetric mesh of the turbocharger model.
5. Volumetric mesh can be achieved only after creating surface mesh successfully, or else the geometry can give fatal errors while volume meshing.